Electropolymerised pH Insensitive Salicylic Acid Reference Systems: Utilization in a Novel pH Sensor for Food and Environmental Monitoring

Abstract

This work summarizes the electrochemical response of a salicylic acid-based carbon electrode for use as a novel solid-state reference electrode in a redox-based pH sensor. This novel reference produces a pH insensitive response over a range of pH 3–10 in solutions with low buffer concentrations, different compositions, conductivities, and ionic strengths is produced. The pH of the local environment is shown to be determined by the chemistry and the electrochemical response of the redox active species on the surface of the electrode; the local pH can be controlled by the electropolymerized salicylic acid moieties due to the acid concentration on the surface, avoiding any perturbation in environmental pH and leading to a stable novel reference system. Sensitivities of −7.1 mV/pH unit, −2.4 mV/pH unit, −0.2 mV/pH unit, and 2.5 mV/pH units were obtained for different food medias, hydroponic solution, seawater, and cell-culture media, respectively, confirming its ability to control the local pH of the electrode. This reference system is paired with a new pH sensing element based on electropolymerized flavanone to provide a calibration free, pH sensitive sensor to effectively and accurately measure the pH of various media with high viscosity, low conductivity, low/high buffer concentration or cell-culture environment, presenting a maximum error of +/−0.03 pH units.

Plasmonic gas sensors based on nanomaterials: mechanisms and recent developments

“…The need for rapid-response and real-time sensing of various gaseous analytes in various applications, such as point-ofcare diagnostics, environmental monitoring, and food safety, has spurred interest in the synthesis of plasmonic nanostructures that can be designed into sensor devices [1][2][3][4][5][6][7][8][9]. While a detailed review of the reported techniques for the synthesis and characterization of plasmonic nanostructures are beyond the scope of this review, in this sub-section, we attempt to give a general idea of the prevalent synthesis protocols and typical characterisation techniques.…”

“…Rapid testing and analysis are urgent societal requirements today, particularly in the fields of environmental monitoring [1][2][3], ultra-fast diagnostics [4][5][6], and food testing [7][8][9]. Thus, the development of sensitive, selective, and efficient sensors is a major thrust area in scientific research.…”

Physical-Vapor-Deposited Metal Oxide Thin Films for pH Sensing Applications: Last Decade of Research Progress

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Liquid Metal pH Morphology Sensor Used for Biological Microenvironment Detection

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